Many industrial components and processes, for example, electronic components and processes, require a rapid and reliable removal of heat during operation in order to prevent overheating and therefore damage or to ensure satisfactory operation of the components or the process. Many components or systems of components such as laser crystals or laser transmitters that are used in satellites require an extremely stable temperature. If convection cooling is impossible and radiant cooling is inadequate, the heat must be dissipated by thermal conduction of suitable heat-conducting materials.
Heat sinks made of alloys based on the best heat-conducting materials, i.e., copper (Cu), silver (Ag) and gold (Au), are usually manufactured for dissipating heat. These metals have a thermal conductivity in the range of 350-400 W/mK. However, the density of Ag, Cu and Au is comparatively high, namely greater than 9 g/cm3, so that heat sinks made of these metals definitely increase the total weight of a device containing them, which is often undesirable. Alloys based on aluminum (Al) have a much lower density (approximately 2.7 g/cm3) but also have a lower thermal conductivity, as low as approximately 220 W/mK at most.
Metal-diamond composite materials having a higher thermal conductivity than the base metal are also known. These materials are produced by infiltration of molten metal into the entire powder bed of a diamond powder or into the entire diamond particle preforms. First, the metal on the preform or the powder bed of diamond is melted in vacuo. Then the melt infiltrates into the powder bed or the preform under the influence of a gas under pressure. However, only elements having a simple and usually flat geometry can be manufactured economically in this way because the mechanical processing or machining of such a composite material is extremely difficult, time-consuming and expensive.
Furthermore, it is known that a component made of metal or a metal alloy can be manufactured in a layer-by-layer construction (also known as a generative production process, rapid prototyping, rapid manufacturing or additive layer manufacturing (ALM)). In this method, a three-dimensional CAD model is cut digitally into thin slices. The digital data is then fed into a control unit, which in turn controls a heat source and the supply of powdered material from which the component is constructed layer by layer in a shape approaching the final contour (English: “near net shape”). The basic principle of construction of a layer is performed by continuous local deposition of metal or a metal alloy in the form of powder or by melting a wire or rod made of the metal or metal alloy, so that the metal or metal alloy is melted and then cooled again by a movable heat source (e.g., a laser or electron beam or electric arc).
Those skilled in the art are familiar with various methods for applying a layer with the help of a powder bed, known in English as direct metal laser sintering (DMLS), selective laser sintering (SLS), selective electron beam melting (SEBM), LaserCusing or selective laser melting (SLM). Those skilled in the art are also familiar with this method of applying a layer by surfacing welding with the aid of a powder feed is known in English as direct metal deposition (DMD), laser engineered net shaping (LENS), laser rapid forming (LRF) or laser cladding (LC).